Population genetic structure and diversity of the East Balkan Swine (Sus scrofa) in Bulgaria, revealed by mitochondrial DNA and microsatellite analyses.

The East Balkan Swine (EBS) is the only indigenous pig breed in Bulgaria. We analyzed the mitochondrial DNA (mtDNA) control region and 21 microsatellite loci for 198 individuals from 11 farms in Bulgaria. Obtained 11 mtDNA haplotypes including three novel ones were grouped to two major clades, European clade E1 (146/198 individuals, 73.7%) and Asian clade A (52/198, 26.3%). The mixture of the two clades may have resulted from historical crossbreeding between the European and Asian pig breeds. Clade A was frequent in southeastern Bulgaria (Burgas Province), but less frequent or absent in northeastern Bulgaria (Varna and Shumen Provinces). The distribution of Europe- and Asia-specific haplotypes relative to EBS farm locations could be attributed to regional differences of breeding systems (e.g., crossbreeding with imported commercial pigs). A microsatellite analysis showed high heterozygosities for all the EBS farms, and negative inbreeding coefficients presumably due to crossing with commercial pigs or wild boars and/or efforts to reduce inbreeding by farmers. Bayesian clustering analyses showed that all farm populations are genetically well distinguishable from one another. Although diversity has been maintained by the efforts of farmers and a breeding association, the effective population size remains small, and conservation efforts should be continued.

p97 and p47 function in membrane tethering in cooperation with FTCD during mitotic Golgi reassembly.

p97ATPase-mediated membrane fusion is required for the biogenesis of the Golgi complex. p97 and its cofactor p47 function in soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) priming, but the tethering complex for p97/p47-mediated membrane fusion remains unknown. In this study, we identified formiminotransferase cyclodeaminase (FTCD) as a novel p47-binding protein. FTCD mainly localizes to the Golgi complex and binds to either p47 or p97 via its association with their polyglutamate motifs. FTCD functions in p97/p47-mediated Golgi reassembly at mitosis in vivo and in vitro via its binding to p47 and to p97. We also showed that FTCD, p47, and p97 form a big FTCD-p97/p47-FTCD tethering complex. In vivo tethering assay revealed that FTCD that was designed to localize to mitochondria caused mitochondria aggregation at mitosis by forming a complex with endogenous p97 and p47, which support a role for FTCD in tethering biological membranes in cooperation with the p97/p47 complex. Therefore, FTCD is thought to act as a tethering factor by forming the FTCD-p97/p47-FTCD complex in p97/p47-mediated Golgi membrane fusion.

Spatio-temporal partitioning facilitates mesocarnivore sympatry in the Stara Planina Mountains, Bulgaria.

The top trophic level in many terrestrial food webs is typically occupied by mammalian carnivores (Order Carnivora) that broadly affect and shape ecosystems through trophic cascades. Their inter-specific interactions can further complicate effects on community dynamics as a consequence of intra-guild competition. The capacity for competitive mammalian carnivores to segregate their hunting and activity regimes is in major part a function of their similarity, in terms of body-size and dietary niche; termed the 'niche variation hypothesis'. In this study, we used camera-trapping to investigate intra-guild interactions and spatio-temporal partitioning among five mesocarnivores, the golden jackal (Canis aureus), European badger (Meles meles), red fox (Vulpes vulpes), European wildcat (Felis sylvestris) and stone marten (Martes foina), in the Stara Planina Mountains, Bulgaria. We collected a total of 444 images of golden jackals, 236 images of European badgers, 200 images of red foxes, 171 images of stone martens, and 145 images of European wildcats, from 6612 camera-days across fifteen camera-trapping stations. With respect to body size, the three smaller species (fox, wildcat and marten) were active in different time periods than the two larger competitors (jackal and badger) through both the warm and cold season. The more similar the trophic niche between species pairs (particularly relating to rodent consumption), the greater the spatio-temporal partitioning we observed within the pair; however, this adapted to seasonal dietary shifts. In conclusion, spatial and temporal (fine-scale and seasonal) niche partitioning appeared to reduce encounter probabilities and competition and may act to facilitate sympatric coexistence among this regional mesocarnivore guild.

Effects of body size on estimation of mammalian area requirements.

Accurately quantifying species' area requirements is a prerequisite for effective area-based conservation. This typically involves collecting tracking data on species of interest and then conducting home-range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on the previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home-range areas with global positioning system (GPS) locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4000 kg. We then applied block cross-validation to quantify bias in empirical home-range estimates. Area requirements of mammals <10 kg were underestimated by a mean approximately15%, and species weighing approximately100 kg were underestimated by approximately50% on average. Thus, we found area estimation was subject to autocorrelation-induced bias that was worse for large species. Combined with the fact that extinction risk increases as body mass increases, the allometric scaling of bias we observed suggests the most threatened species are also likely to be those with the least accurate home-range estimates. As a correction, we tested whether data thinning or autocorrelation-informed home-range estimation minimized the scaling effect of autocorrelation on area estimates. Data thinning required an approximately93% data loss to achieve statistical independence with 95% confidence and was, therefore, not a viable solution. In contrast, autocorrelation-informed home-range estimation resulted in consistently accurate estimates irrespective of mass. When relating body mass to home range size, we detected that correcting for autocorrelation resulted in a scaling exponent significantly >1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum.

Efectos del Tamaño Corporal sobre la Estimación de los Requerimientos de Área de Mamíferos Resumen La cuantificación precisa de los requerimientos de área de una especie es un prerrequisito para que la conservación basada en áreas sea efectiva. Esto comúnmente implica la recolección de datos de rastreo de la especie de interés para después realizar análisis de la distribución local. De manera problemática, la autocorrelación en los datos de rastreo puede resultar en una subestimación grave de las necesidades de espacio. Con base en trabajos previos, formulamos una hipótesis en la que supusimos que la magnitud de la subestimación varía con la masa corporal, una relación que podría tener implicaciones serias para la conservación. Para probar esta hipótesis en mamíferos terrestres, estimamos las áreas de distribución local con las ubicaciones en GPS de 757 individuos de 61 especies de mamíferos distribuidas mundialmente con una masa corporal entre 0.4 y 4,000 kg. Después aplicamos una validación cruzada en bloque para cuantificar el sesgo en estimaciones empíricas de la distribución local. Los requerimientos de área de los mamíferos <10 kg fueron subestimados por una media ∼15% y las especies con una masa ∼100 kg fueron subestimadas en ∼50% en promedio. Por lo tanto, encontramos que la estimación del área estaba sujeta al sesgo inducido por la autocorrelación, el cual era peor para las especies de talla grande. En combinación con el hecho de que el riesgo de extinción incrementa conforme aumenta la masa corporal, el escalamiento alométrico del sesgo que observamos sugiere que la mayoría de las especies amenazadas también tienen la probabilidad de ser aquellas especies con las estimaciones de distribución local menos acertadas. Como corrección, probamos si la reducción de datos o la estimación de la distribución local informada por la autocorrelación minimizan el efecto de escalamiento que tiene la autocorrelación sobre las estimaciones de área. La reducción de datos requirió una pérdida de datos del ∼93% para lograr la independencia estadística con un 95% de confianza y por lo tanto no fue una solución viable. Al contrario, la estimación de la distribución local informada por la autocorrelación resultó en estimaciones constantemente precisas sin importar la masa corporal. Cuando relacionamos la masa corporal con el tamaño de la distribución local, detectamos que la corrección de la autocorrelación resultó en un exponente de escalamiento significativamente >1, lo que significa que el escalamiento de la relación cambió sustancialmente en el extremo superior del espectro de la masa corporal.

Evolution of MHC class I genes in Eurasian badgers, genus Meles (Carnivora, Mustelidae).

Because of their role in immune defense against pathogens, major histocompatibility complex (MHC) genes are useful in evolutionary studies on how wild vertebrates adapt to their environments. We investigated the molecular evolution of MHC class I (MHCI) genes in four closely related species of Eurasian badgers, genus Meles. All four species of badgers showed similarly high variation in MHCI sequences compared to other Carnivora. We identified 7-21 putatively functional MHCI sequences in each of the badger species, and 2-7 sequences per individual, indicating the existence of 1-4 loci. MHCI exon 2 and 3 sequences encoding domains α1 and α2 exhibited different clade topologies in phylogenetic networks. Non-synonymous nucleotide substitutions at codons for antigen-binding sites exceeded synonymous substitutions for domain α1 but not for domain α2, suggesting that the domains α1 and α2 likely had different evolutionary histories in these species. Positive selection and recombination seem to have shaped the variation in domain α2, whereas positive selection was dominant in shaping the variation in domain α1. In the separate phylogenetic analyses for exon 2, exon 3, and intron 2, each showed three clades of Meles alleles, with rampant trans-species polymorphism, indicative of the long-term maintenance of ancestral MHCI polymorphism by balancing selection.

Badger setts provide thermal refugia, buffering changeable surface weather conditions.

Den use can be crucial in buffering environmental conditions and especially to provide an insulated environment for raising altricial young. Through Sept-Dec 2016 we monitored temperature and humidity at 11 badger setts (burrow systems), using thermal probes inserted over 4-13 sett entrances to a depth of ca. 2 m, supplemented by continuous daily logging at one entrance per sett. Setts were cooler than exterior conditions Sept-Oct, and warmer than exterior conditions Nov-Dec. Setts cooled down when badgers left them to forage by night, and warmed up when badgers occupied them by day. Soil type and aspect also influenced sett temperature. Sett temperature did not affect the weight or body-condition of either adults or maturing cubs in autumn. However, cubs born into setts that were relatively warmer through the preceding autumn-winter were heavier in the following spring than contemporaries born in cooler setts (badgers exhibit delayed implantation), and so warmer setts might benefit early cub growth. We posit that sett quality may be important in providing badgers with a stable thermal refuge from variable weather conditions. More broadly, den use may buffer climate change effects for many fossorial carnivore species.

A Comparison of Visual and Genetic Techniques for Identifying Japanese Marten Scats - Enabling Diet Examination in Relation to Seasonal Food Availability in a Sub-Alpine Area of Japan.

We compared the reliability of visual diagnostic criteria to DNA diagnostic techniques, including newly designed primers, to discriminate Japanese marten (Martes melampus) feces from those of other sympatric carnivore species. Visual criteria proved > 95% reliable for fresh, odoriferous scats in good condition. Based upon this verification, we then examined if and how Japanese marten diet differs among seasons at high elevation study site (1500-2026 m). We also considered how intra-specific competition with the Japanese red fox (Vulpes vulpes japonica) may shape marten feeding ecology. From 120 Japanese marten fecal samples, high elevation diet comprised (frequency of occurrence) 30.6-66.0% mammals, 41.0-72.2% insects and 10.6-46.2% fruits, subject to seasonal variation, with a Shannon-Weaver index value of 2.77. These findings contrast substantially to seasonal marten diet reported in adjacent lowland regions (700-900 m), particularly in terms of fruit consumption, showing the trophic adaptability of the Japanese marten. We also noted a substantial dietary overlap with the red fox (n = 26 scats) with a Shannon-Weaver index of 2.61, inferring little trophic niche mutual exclusion (trophic niche overlap: 0.95), although some specific seasonal prey selection differences were likely related to relative differences in body size between foxes and martens. This additional information on the feeding ecology of the Japanese marten enables a better assessment of the specific risks populations face in mountainous regions.

Population Structure of the Raccoon Dog on the Grounds of the Imperial Palace, Tokyo, Revealed by Microsatellite Analysis of Fecal DNA.

The raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) is highly adaptable to urban environments. Populations of carnivorans inhabiting urban areas sometimes differ ecologically and genetically from those in rural areas. However, there is little information on urban raccoon dogs. This study focused on raccoon dog populations in Tokyo, one of the most highly urbanized cities in the world. We examined the genotypes of 10 microsatellites for 101 fecal samples from raccoon dogs inhabiting the grounds of the Imperial Palace, a green space in central Tokyo. We successfully genotyped 58 samples originating from 31 individuals. We also analyzed muscle tissue samples from raccoon dogs from the grounds of the Imperial Palace, the Akasaka Imperial Grounds (a green space close to the Imperial Palace), and the surrounding urban area, and then investigated the genetic structure and diversity of these populations, and the genetic differentiation among them. The population on the grounds of the Imperial Palace was genetically differentiated from that in the Akasaka Imperial Grounds, suggesting that the roads and buildings act as barriers to gene flow. In addition, the population on the grounds of the Imperial Palace showed greater genetic difference from that in the surrounding area than that in the Akasaka Imperial Grounds. We speculate that the moats around the Imperial Palace restrict individual ranges within the palace grounds and limit migration and gene flow to other areas.

Molecular phylogeography of the brown bear (Ursus arctos) in Northeastern Asia based on analyses of complete mitochondrial DNA sequences.

To further elucidate the migration history of the brown bears (Ursus arctos) on Hokkaido Island, Japan, we analyzed the complete mitochondrial DNA (mtDNA) sequences of 35 brown bears from Hokkaido, the southern Kuril Islands (Etorofu and Kunashiri), Sakhalin Island, and the Eurasian Continent (continental Russia, Bulgaria, and Tibet), and those of four polar bears. Based on these sequences, we reconstructed the maternal phylogeny of the brown bear and estimated divergence times to investigate the timing of brown bear migrations, especially in northeastern Eurasia. Our gene tree showed the mtDNA haplotypes of all 73 brown and polar bears to be divided into eight divergent lineages. The brown bear on Hokkaido was divided into three lineages (central, eastern, and southern). The Sakhalin brown bear grouped with eastern European and western Alaskan brown bears. Etorofu and Kunashiri brown bears were closely related to eastern Hokkaido brown bears and could have diverged from the eastern Hokkaido lineage after formation of the channel between Hokkaido and the southern Kuril Islands. Tibetan brown bears diverged early in the eastern lineage. Southern Hokkaido brown bears were closely related to North American brown bears.

Comparative molecular phylogeny and evolution of sex chromosome DNA sequences in the family Canidae (Mammalia: Carnivora).

To investigate the molecular phylogeny and evolution of the family Canidae, nucleotide sequences of the zinc-finger-protein gene on the Y chromosome (ZFY, 924-1146 bp) and its homologous gene on the X chromosome (ZFX, 834-839 bp) for twelve canid species were determined. The phylogenetic relationships among species reconstructed by the paternal ZFY sequences closely agreed with those by mtDNA and autosomal DNA trees in previous reports, and strongly supported the phylogenetic affinity between the wolf-like canids clade and the South American canids clade. However, the branching order of some species differed between phylogenies of ZFY and ZFX genes: Cuon alpinus and Canis mesomelas were included in the wolf-like canid clades in the ZFY tree, whereas both species were clustered in a group of Chrysocyon brachyurus and Speothos venaticus in the ZFX tree. The topology difference between ZFY and ZFX trees may have resulted from the two-times higher substitution rate of the former than the latter, which was clarified in the present study. In addition, two types of transposable element sequence (SINE-I and SINE-II) were found to occur in the ZFY final intron of the twelve canid species examined. Because the SINE-I sequences were shared by all the species, they may have been inserted into the ZFY of the common ancestor before species radiation in Canidae. By contract, SINE-II found in only Canis aureus could have been inserted into ZFY independently after the speciation. The molecular diversity of SINE sequences of Canidae reflects evolutionary history of the species radiation.

VCIP135 deubiquitinase and its binding protein, WAC, in p97ATPase-mediated membrane fusion.

Two distinct p97 membrane fusion pathways are required for Golgi biogenesis: the p97/p47 and p97/p37 pathways. VCIP135 is necessary for both pathways, while its deubiquitinating activity is required only for the p97/p47 pathway. We have now identified a novel VCIP135-binding protein, WAC. WAC localizes to the Golgi as well as the nucleus. In Golgi membranes, WAC is involved in a complex containing VCIP135 and p97. WAC directly binds to VCIP135 and increases its deubiquitinating activity. siRNA experiments revealed that WAC is required for Golgi biogenesis. In an in vitro Golgi reformation assay, WAC was necessary only for p97/p47-mediated Golgi reassembly, but not for p97/p37-mediated reassembly. WAC is hence thought to function in p97/p47-mediated Golgi membrane fusion by activating the deubiquitinating function of VCIP135. We also showed that the two p97 pathways function in ER membrane fusion as well. An in vitro ER reformation assay revealed that both pathways required VCIP135 but not its deubiquitinating activity for their ER membrane fusion. This was consistent with the finding that WAC is unnecessary for p97-mediated ER membrane fusion.

Phylogeographic sympatry and isolation of the Eurasian badgers (Meles, Mustelidae, Carnivora): Implications for an alternative analysis using maternally as well as paternally inherited genes.

In the present study, to further understand the phylogenetic relationships among the Eurasian badgers (Meles, Mustelidae, Carnivora), which are distributed widely in the Palearctic, partial sequences of the mitochondrial DNA (mtDNA) control region (539-545 base-pairs) as a maternal genetic marker, and the sex-determining region on the Y-chromosome gene (SRY: 1052-1058 base-pairs), as a paternal genetic marker, were examined. The present study revealed ten SRY haplotypes from 47 males of 112 individuals of the Eurasian Continent and Japan. In addition, 39 mtDNA haplotypes were identified from those animals. From the phylogeography of both the uniparentally inherited genes, four lineages were recognized as Japanese, eastern Eurasian, Caucasian, and western Eurasian. The distribution patterns of the mtDNA lineages showed the existence of a sympatric zone between the eastern and western Eurasian lineages around the Volga River in western Russia. Furthermore, the present study suggested that in the Japanese badgers, the larger genetic differentiation of the Shikoku population was attributable to geographic history in the Japanese islands.

Phosphorylation of p37 is important for Golgi disassembly at mitosis.

In mammals, the Golgi apparatus is disassembled at early mitosis and reassembled at the end of mitosis. For Golgi disassembly, membrane fusion needs to be blocked. Golgi biogenesis requires two distinct p97ATPase-mediated membrane fusion, the p97/p47 and p97/p37 pathways. We previously reported that p47 phosphorylation on Serine-140 by Cdc2 results in mitotic inhibition of the p97/p47 pathway [11]. In this study, we demonstrate that p37 is phosphorylated on Serine-56 and Threonine-59 by Cdc2 at mitosis, and this phosphorylated p37 does not bind to Golgi membranes. Using an in vitro Golgi reassembly assay, we show that mutated p37(S56D, T59D), which mimics mitotic phosphorylation, does not cause any cisternal regrowth, indicating that p37 phosphorylation inhibits the p97/p37 pathway. Our results demonstrate that p37 phosphorylation on Serine-56 and Threonine-59 is important for Golgi disassembly at mitosis.

Isolation of a point-mutated p47 lacking binding affinity to p97ATPase.

p47, a p97-binding protein, functions in Golgi membrane fusion together with p97 and VCIP135, another p97-binding protein. We have succeeded in creating p47 with a point mutation, F253S, which lacks p97-binding affinity. p47 mapping experiments revealed that p47 had two p97-binding regions and the F253S mutation occurred in the first p97-binding site. p47(F253S) could not form a complex with p97 and did not caused any cisternal regrowth in an in vitro Golgi reassembly assay. In addition, mutation corresponding to the p47 F253S mutation in p37 and ufd1 also abolished their binding ability to p97.

Origins and founder effects on the Japanese masked palm civet Paguma larvata (Viverridae, Carnivora), revealed from a comparison with its molecular phylogeography in Taiwan.

The source areas of the Japanese populations of the masked palm civet Paguma larvata (Viverridae, Carnivora), an alien species in Japan, have not been identified. In the present study, to reveal their origins and genetic features, we determined the full mitochondrial DNA cytochrome b sequences (1,140 base-pairs) of a total of 206 individuals of P. larvata from the Honshu and Shikoku islands of Japan (186 animals) and Taiwan (20 animals), and investigated their molecular phylogeography and the genetic relationships between populations in these countries. We found that each animal from Japan exhibited one of four haplotypes (JA1, JA2, JA4, and JA5), and that JA1 and JA4 were more frequent in eastern Honshu and Shikoku-central Honshu, respectively. By contrast, six haplotypes consisting of four new types (TW1, TW2, TW3, and TW4) and the previously reported two types (JA1 and JA4) were identified from 20 animals from native populations in Taiwan. Within Taiwan, one haplotype set (JA1, TW1, and TW2) was distributed in the western region, while a second (JA4, TW3, and TW4) was found in the eastern region; these regions are separated by high mountain ranges. Our comparison of haplotype distributions strongly demonstrated that the eastern Japanese populations originated from animals of western Taiwan, and that the western Japanese populations originated from those of eastern Taiwan. In addition, the lower genetic variability and particular distribution patterns of haplotypes in Japan showed founder effects, which may have resulted from multiple introductions of P. larvata to Japan from Taiwan.

The H-Invitational Database (H-InvDB), a comprehensive annotation resource for human genes and transcripts.

Here we report the new features and improvements in our latest release of the H-Invitational Database (H-InvDB; http://www.h-invitational.jp/), a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of full-length cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB_4.6. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 (98.1%) protein-coding and 642 (1.9%) non-protein-coding loci; 858 (2.5%) transcribed loci overlapped with predicted pseudogenes. For all these transcripts and genes, we provide comprehensive annotation including gene structures, gene functions, alternative splicing variants, functional non-protein-coding RNAs, functional domains, predicted sub cellular localizations, metabolic pathways, predictions of protein 3D structure, mapping of SNPs and microsatellite repeat motifs, co-localization with orphan diseases, gene expression profiles, orthologous genes, protein-protein interactions (PPI) and annotation for gene families. The current H-InvDB annotation resources consist of two main views: Transcript view and Locus view and eight sub-databases: the DiseaseInfo Viewer, H-ANGEL, the Clustering Viewer, G-integra, the TOPO Viewer, Evola, the PPI view and the Gene family/group.

Evola: Ortholog database of all human genes in H-InvDB with manual curation of phylogenetic trees.

Orthologs are genes in different species that evolved from a common ancestral gene by speciation. Currently, with the rapid growth of transcriptome data of various species, more reliable orthology information is prerequisite for further studies. However, detection of orthologs could be erroneous if pairwise distance-based methods, such as reciprocal BLAST searches, are utilized. Thus, as a sub-database of H-InvDB, an integrated database of annotated human genes (http://h-invitational.jp/), we constructed a fully curated database of evolutionary features of human genes, called 'Evola'. In the process of the ortholog detection, computational analysis based on conserved genome synteny and transcript sequence similarity was followed by manual curation by researchers examining phylogenetic trees. In total, 18 968 human genes have orthologs among 11 vertebrates (chimpanzee, mouse, cow, chicken, zebrafish, etc.), either computationally detected or manually curated orthologs. Evola provides amino acid sequence alignments and phylogenetic trees of orthologs and homologs. In 'd(N)/d(S) view', natural selection on genes can be analyzed between human and other species. In 'Locus maps', all transcript variants and their exon/intron structures can be compared among orthologous gene loci. We expect the Evola to serve as a comprehensive and reliable database to be utilized in comparative analyses for obtaining new knowledge about human genes. Evola is available at http://www.h-invitational.jp/evola/.

Helical microtubule arrays in a collection of twisting tubulin mutants of Arabidopsis thaliana.

Anisotropic expansion of plant cells requires organized arrays of cortical microtubules. Mutations in microtubule-associated proteins and a particular mutation in alpha-tubulins were reported to cause abnormal microtubule arrays and result in helical growth in Arabidopsis thaliana. However, the way in which these mutations affect the organization of microtubules remains unknown. We here identified 32 Arabidopsis twisting mutants that have either missense or amino acid deletion mutations in alpha- or beta-tubulins. Mutations were mapped to the GTPase-activating region in alpha-tubulin, intra- and interdimer interfaces of tubulin heterodimers, and lateral contact regions among adjacent protofilaments. These dominant-negative tubulin mutants were incorporated into the microtubule polymer and formed shallow helical arrays of distinct handedness along the long axis of the root epidermal cells. A striking correlation exists between the direction in which cortical helical arrays are skewed and the growth direction of elongating roots. The GTPase-activating-region mutant had left-handed helical arrays composed of highly stabilized microtubules, which could be decorated along the entire microtubule lattices with the otherwise tip-localized End Binding 1 protein. A mutation at the intradimer interface, on the other hand, generated highly dynamic microtubules and right-handed helical arrays. Cortical microtubules in wild type and these two tubulin mutants were composed mainly of 13 protofilaments. This comprehensive analysis of tubulin mutations provides insights into the mechanism by which tubulin structures influence microtubule dynamics and organization.

p37 is a p97 adaptor required for Golgi and ER biogenesis in interphase and at the end of mitosis.

We previously reported that p97/p47-assisted membrane fusion is important for the reassembly of organelles at the end of mitosis, but not for their maintenance during interphase. We have now identified a p97 adaptor protein, p37, which forms a complex with p97 in the cytosol and localizes to the Golgi and ER. siRNA experiments revealed that p37 is required for Golgi and ER biogenesis. Injection of anti-p37 antibodies into cells at different cell cycle stages showed that p37 plays an important role in both Golgi and ER maintenance during interphase as well as in their reassembly at the end of mitosis. In an in vitro Golgi reassembly assay, the p97/p37 complex has membrane fusion activity. In contrast to the p97/p47 pathway, this pathway requires p115-GM130 tethering and SNARE GS15, but not syntaxin5. Interestingly, although VCIP135 is also required, its deubiquitinating activity is unnecessary for p97/p37-mediated activities.